Contour-cap for armor-piercing projectiles.



C. DAVIS. CONTOUR CAP FOR ARMOR PIERGING PROJECTILES.

APPLICATION FILED NOV.11,1914.

1,132,453, Patented Mar. 16, 1915.

( ave/who LX910 1711 gms;

61mm 14% f UNITED STATES PATENT OFFICE.

CLELAND DAVIS, 01 THE UNITED STATES NAVY, AssmNoR 10 ORDNANCE DEVELOP- MENT COMPANY OE AMERICA, OFWLLMINGXON, DELAWARE, ACOBBORATION 01? DELAWARE.

CONTOUR-CAP FOB ARMOR-PIEEMNG PROJECTILES.

To all whom it may concern:

Be it known that I, CLELAND DAVIS, commander United States Navy, a citizen of the United States, stationed at SairDiego, in the county of San Diego and State of California, have invented certain new and useful Improvements in Contour-Caps for Armor- Piercing Projectiles; and I do hereby declare. the following. to [ma full, clear. and exact description of the invention, such as will enable otherssk'illed in the art to which it appertains to make and use the same.

My present invention relates to caps for armor piercing projectiles, whereby there is combined, with the projectile, a hood of such a character as to give the form or contour to the whole that is best adapted to a minimum resistance of the projectile in its flight through the air thus causing it to have a greater range, a flatter trajectory, a greater danger space and a greater velocity at impact for a given range, and at the same time preserve it iii a state of the greatest ctliciency for the penetration of the armor. My Patent, No. 945,492, granted January 4, 1910, provided for these qualities in an armor piercing projectile as has been demonstrated by the general use of the construction therein described. My present invention is an improvement on that design, principally from a manufacturing point of view.

In order to give a better understanding of the nature of my invention, 1 will give briefly the generally-accepted theory of the resistance of face hardened armor and the function of the soft steel cap now universally uscd on all armor piercing projectiles.

First, when a pointed projectile strikes the hard elastic face of an armor plate, there occurs an elastic or diaphragmatic dishing of the hard face, which distributes the re sistance over a considerable area and causes the stress of impact to react upon the pro jectile and tend to sto it in a distance equal to the versed sine of t 10 dished face. It the projectile is strong enough to withstand the force of impact without breaking up and, if it have sufficient velocity after the energy required to elastically dish the hard plate has been expended upon it, then penetration begins to occur and the resistance of the plate becomes purely local, the amount Specification of Letters Patent. Pat t d Mar. 16, 1915. Application filed November 11, 1914 semi No. 851,515. r

of penetration depending upon the remaining velocity. of the projectile. K

Now let us observe what happens when the shell fitted with av soft steel cap surrounding and inclosing the point strikes a hard face armored plate. When the mass, consisting of the capai d shell, strikes the hard face of the armor. plate, the energy of impact of the whole mass is transmitted to the plate through the soft steel cap, which must be strong enough to perform this functi .n, and there occuis the same elastic or diaphragn'iatic dishing, that ortion of the energy of impact required or the elastic dishing being concentrated as before at the point of impact, and tending to stop the impinging shell: but the work done on the projectile by the resistance oll'ered by the plate, in the elastic dishing caused by the impact. instead of being concentrated on the projectile, during the time it takes for the projectile to move through the space equal to the versed sine of the dished face, is in this case distributed over a considerably greater distance, or that equal to the versed sine of the dishing. plus the distance the point of the projectile has to travel in piercing the soft steel cap, remembering that the cap itself, while strong enough to transmit the stress of impact to the plate, ollers little resistance to the passage through it of the hard point of the shell; obviously then the work done on the shell upon impact brings much less strain upon the shell fitted with a soft steel cap than upon a shell striking without a cap. greatly decreasing the tendency of the shell to break.

Now a sicll provided with a soft stee'i cap, which facilitates its penetration in urmor, is not of a form that will give the best results in its flight through the air, before the projectile can hit the target. In other words, the best form for penetrating armor is n t the best form for flight, and the convcrse of this is also true, the reasons being 7 known to all who are familiar with the art.

contour that would offer minimum resistance in the passage of the projectile through the air.

Many forms of caps have been tried; solid caps of steel, caps made partly of steel and partly of frangible material, the latter being attached to the steel cap proper, and the idea being that the frangible material would be destroyed and dissipated and thus not interfere with the functioning of the soft steel cap proper; and finally, caps in which the forward or contour portion has been hollowed or chambered out-this latter, as disclosed in my Patent No. 945,492, has been the only form that has successfully combined the two qualities, (a) of the mcst desirable form for penetration and (b) the mcst desirable form for flight.

In order to lead to a better understanding of my invention, which will hereinafter be explained, I will give the causes of the failure of the long pointed solid cap, both the one of solid steel and the one with the frangible point. In the case of the long pointed solid cap, referring again to the theory of the resistance of face hardened armor as above given, when the mass consisting of the shell and the long pointed solid cap strikes the hard faced plate, there occurs the same diaphragmatic dishing as before, the stress of impact being transmitted to the plate through the cap and the projectile continuing on its way through the cap which offers comparatively little resistance to its progress, but by the time the point of the projectile has gone through the cap and reached the plate, the elastic reaction of the hard face of the plate has caused it to spring back to its original plane and the effect of the )reliminary blow is lost; in other words, there must be a definite distance between the point of the projectile and the extreme front end of the cap, and this distance must be such that the point of the projectile after it has pierced the cap should reach the plate when the latter is at the point of maximum depression and before it has had time to react.

It will be cbserved that there is a very delicate adjustment required of the time element; the soft cap should be of such character that it will transmit the energy of impact of the mass of the shell and cap and deress the plate to the point of its elastic imit and at the same time offer small resistance to the passage of the shell through it; and also should permit the point of the shell to go through it and arrive at the plate at the very instant when the latter has reached the point of maximum depression and can offer only a local resistance to the shell.

In the case where frangible material has been used to form a forward portion of the 65 cap, it has been composed of a hard and more or less resisting substance, the theory being that on account of its brittleness it would be quickly destroyed and dissipated and leave the way clear for the steel cap proper to perform its function, but these efforts also failed to give results, because the substance offered sullicient compressive resistance to hold the soft steel cap and enable the point of the projectile to pass through it so that when the latter reached the plate, the effect was the same as if the projectile had no cap at all.

Now in the case of the cap, with the hollowed or chambered fore portion, which is shown in my Patent No. E)l5l92 aforesaid, the effect is as follows:The walls being ductile, upon impact, are mashed back upon and become in fact part of the cap itself, so that the function of the latter is not interfered with. There are, however, certain difficulties connected with manufacture of these hollow caps that it is desirable to avoid, and so I propose to provide in place of the hollowed or chambered portion of the cap as disclosed in said patent, a solid-portion of easily compressible material of a pointed form, to give the best contour for a minimum resistance, such as soft rubber, the outer surface of which may be hardened so as to preserve its shape in ilight and to protect it in handling, or it may be incased in another shell of vulcanized rubber, or other form of casing, to give it the requisite shape to preserve it in handling and in flight.

My invention will be understood by reference to the accompanying drawings, in which similar parts are indicated by similar reference numerals throughout the several views.

Figure 1 is a side elevation of the shell with the improved cap attached; Fig. 2 shows a central vertical section through the soft metal cap and contour cap, with the nose of the shell shown in elevation; and Fig. 3 is a similar section of a modified form of soft metal cap and contour cap constructed according to my invention.

Referring to Figs. 1 and 2, A shows the shell having the usual ogival point A. 13 represents the soft metal cap which'is provided with an annular rib b on the forward end thereof, and to which the contour cap C is attached in any convenient way, as by screw bolts or rivets D. The core of this contour cap C is preferably of soft rubber, while the outer layers 0 are hardened so as to supply sufiicient rigidity to the cap in its flight from the chamber of the gun to the target. Instead of having the contour cap formed of the same mass of rubber shown in Fig. 2, I may provide a separate contour cap C, as shown in Fig. 3, with a core C of rubber or other suitable material. This contour cap C may be made of hard rubber,

metal, or other suitable material, and may be attached to the soft metal cap B in any convenient way, as by screwing same onto the screw threads b provided on the nose 6' of the soft metal cap B.

The action of this device is as follows When an armor piercing projectile, fitted with a soft steel cap to facilitate enetration and a point of easily compressib e material of such form as to give the best contour for flight, meets the hard face of an armor plate, the contour point is compressed upon itself; the resistance it offers not being sulficient to hold a soft steel cap and enable the point of the ro'ectile to pass through it and so reach the ace of the plate before the cap itself does. The whole effect being that the compressible contour point while it performs its function to give the projectile the form best suited to a sustained flight through'the air does not interfere with its owers of penetration; in other words, it eaves the projectile with its soft steel cap in a condition to attack the plate with its powers of penetration unimpaired.

It will be obvious that various modifications might be made in the form of the contour cap and in the mode of attaching it to the projectile which could be used without de arting from the spirit of my invention.

aving thus described my invention what I claim and desire to secure by Letters Patent of the United States is:-

1. The combination with a pointed armor piercing projectile, of a soft metal cap secured to the nose of the projectile and stirrounding and supporting the point thereof, and a solid contour cap secured to the soft metal cap and tapered to reduce the resistance of the atmosphere to the flight of the projectile, the said contour ca having a core of soft yielding non-metal ic material, and the said contour cap with its core being adapted to yield when the Projectile strikes the target without inter erin with the proper operation of the pro'ecti e at the moment of impact, substantia ly as described.

2. The combination with a pointed armor piercing projectile, of a soft metal cap secured to the nose of the projectile and surrounding and supporting the point thereof, and a solid contour cap secured to the soft metal cap and tapered to reduce the resistance of the atmosphere to the flight of the projectile, the said contour cap having a core of soft rubber, and the said contour cap with its core being adapted to yield when the rojectile strikes the target without intererin'g with the proper operation of the proectile at the moment of impact, substantially as described.

3. The combination with a pointed armor piercing projectile, of a soft metal cap secured to the nose of the projectile and surrounding and supporting the point thereof, and a solid contour cap secured to the soft metal cap and tapered to reduce the resistance of the atmos here to the flight of the projectile, the sai contour cap having an outer inclosing shell of sufficient rigidity to retain its shape during the travel of the projectile, and a core of soft yielding non-metallic material, and the said contour cap with its core being adapted to yield when the projectile strikes the target without interfering with the proper operation of the projectile at the moment of impact, substantially as described.

4. The combination with a pointed armor piercing projectile, of a soft metal cap secured to the nose of the projectile and surrounding and supporting the point thereof, and a solid contour cap secured to the soft metal cap and tapered to reduce the resistance of the atmos here to the fli ht of the projectile, the sai contour cap aving an outer inclosing shell of suflicient ri idity to retain its shape durin the travel 0 the projectile, and a core 0 soft rubber, and the said contour cap with its core being adapted to yield when the projectile strikes the target without interfering with the proper operation of the projectile at the moment of impact, substantially as described.

5. The combination with a pointed armor piercing projectile, of a soft metal cap secured to the nose of the projectile and surrounding and supporting the point thereof, and a solid contour cap secured to the soft metal cap and tapered to reduce the resistance of the atmosphere to the flight of the projectile, the sai contour cap com rising a mass of soft rubber adapted to yiel when the projectile strikes the target without interfering with the proper operation of the projecti e at the moment of impact, substantial y as described.

In testimony whereof, I aflix my signature, in presence of two witnesses.

CLELAND DAVIS.

Witnesses:

Gnoaos P. Prrxm, Hsanaar W. CHI'I'I'ENDEN. 

